Method for Simultaneous Transmission of High-Frequency Transmission Signals via a Common High-Frequency Line

ABSTRACT

A method for simultaneous transmission of at least two high-frequency transmission signals via a common high-frequency line includes providing at least two input signals at respective inlet ports. The input signals are signals of a same carrier frequency. From the input signals, respective transmission signals are provided with different transmission frequencies from each other and from the carrier frequency by mixing the input signals using one frequency mixer each. The frequency mixers are supplied with respective mixer oscillator signals. The transmission signals are transmitted via the common high-frequency line. The mixer oscillator signals are provided from a same oscillator signal.

This application claims the benefit of DE 10 2012 211 312.6, filed onJun. 29, 2012, which is hereby incorporated by reference.

BACKGROUND

The present embodiments relate to simultaneous transmission of at leasttwo high-frequency transmission signals via a common high-frequencyline.

In magnetic resonance devices, magnetic resonance signals may bereceived with the aid of local coils. Images may be generated during amagnetic resonance scan. For good imaging, the received magneticresonance signals are to have a relatively high signal-to-noise ratio.In magnetic resonance tomography, the magnetic resonance signalsprovided or received are transmitted with a cable connection to anelectronic computing device or evaluation device. The electroniccomputing device or the evaluation device then processes the receivedmagnetic resonance signals further. Because many local coils may bepresent, and each local coil provides one magnetic resonance signal(e.g., input signal) respectively, a relatively large amount of cablingwork is to be performed. Efforts are therefore made to transmit severalmagnetic resonance signals via a common high-frequency line. Thus, in US2009/286478 A1, the transmission of two magnetic resonance signals percable is proposed. In this method, implementation takes place with theaid of a corresponding signal transmission device that is arranged inthe vicinity of the local coils. With this signal transmission, variousoscillator signals are provided for the frequency mixer. An individualLO frequency is thus provided per channel. This uses correspondinglycomplex frequency crossovers for the separation of different LOfrequencies (e.g., local oscillator frequency).

SUMMARY AND DESCRIPTION

The scope of the present invention is defined solely by the appendedclaims and is not affected to any degree by the statements within thissummary.

The present embodiments may obviate one or more of the drawbacks orlimitations in the related art. For example, an improved method and animproved signal transmission device with which at least twohigh-frequency transmission signals may be transmitted via a commonhigh-frequency line with minimum effort are provided.

A method is for simultaneous transmission of at least two high-frequencytransmission signals via a common high-frequency line. At least twoinput signals (e.g., receive signals of a magnetic resonance tomographysystem) are provided at respective inlet ports, where the input signalshave an equal or roughly equal carrier frequency that is, for example,around the Larmor frequency. From the input signals, respectivetransmission signals are provided with transmission frequenciesdifferent from each other and from the carrier frequency. This isachieved by mixing the input signals using one frequency mixer each. Thefrequency mixers are supplied with respective mixer oscillator signals.The transmission signals generated from the mixer oscillator signals aretransmitted via the common high-frequency line. The mixer oscillatorsignals are supplied by the same oscillator signal.

In one or more of the present embodiments, a mixer oscillator signal maybe a signal that is obtained from the common oscillator signal andsupplied directly to the respective mixer or fed into the mixer.

To supply the frequency mixers, therefore, only one single, commonoscillator signal that may be divided between the at least two frequencymixers or from which the mixer oscillator signals for the at least twofrequency mixers are provided is provided. Only a single oscillatorsignal (e.g., a single LO frequency) is to be transmitted from theelectronic processing device, where the common oscillator signal may betransmitted via the common high-frequency line to the frequency mixers.The method according to one or more of the present embodiments thereforeresults in a clear reduction in work overall with regard to the supplyof the frequency mixers, because the existing oscillator signal may beused at least twice. The use of a filter to separate different LOfrequencies or different oscillator signals with the associateddisadvantages with regard to cost and valuable installation space isrendered unnecessary. In addition, unwanted mixed products and noisecouplings that may arise from incomplete separation of differentoscillator signals are avoided as a result. This may be advantageous inthe case of a magnetic resonance tomography system in which a relativelyhigh signal-to-noise ratio is required.

In one embodiment, at least three transmission signals are transmittedvia the common high-frequency line. For example, at least three inputsignals of the same or approximately the same carrier frequency may beprovided, and one of the input signals may be directly transmittedunmixed as a transmission signal with the carrier frequency via thecommon high-frequency line. Therefore, if three input signals areprovided, then two of the input signals may be mixed with the aid ofrespective frequency mixers and thus converted into respectivetransmission signals with different frequencies, while a third inputsignal may be transmitted directly and therefore unmixed with thecarrier frequency via the common high-frequency line. Consequently, thenumber of transmitted signals may be further increased, furthermoreminimizing the cabling. In addition, the input signal also obviates theneed to use an additional frequency mixer with the associated mixeroscillator signal, saving both expense and valuable installation space.

In one embodiment, the oscillator signal for the provision of therespective mixer oscillator signals is transmitted via the commonhigh-frequency line to the frequency mixers. This provides that thetransmission signals are transmitted via the common high-frequency linewhile in the opposite direction, the oscillator signal is transmitted.An additional high-frequency line for transmission of the oscillatorsignal may thus be saved.

In one embodiment, at least two mixer oscillator signals provided fromthe same oscillator signal have the same frequency. At least twofrequency mixers that provide corresponding transmission signals maytherefore be supplied with mixer oscillator signals of the samefrequency. In this embodiment, one of the frequency mixers is an upconverter, and the other frequency mixer is a down converter. One of theinput signals is thus mixed upward while the other input signal is mixeddownward. Two transmission signals with completely differenttransmission frequencies are thus obtained, enabling the transmissionsignals to be transmitted via the common high-frequency line without thetransmission signals influencing each other. In addition, thisembodiment has the advantage that the same mixer oscillator signals areprovided, and consequently, the common oscillator signal does not haveto be converted with the aid of a frequency divider or a frequencymultiplier. Two oscillator signals do not have be separated from eachother again with the aid of an LO channel filter.

In one embodiment, different mixer oscillator signals are generated fromthe common oscillator signal in order to enable mixing in differentfrequency positions. Thus, for example, at least one mixer oscillatorsignal may be generated from the common oscillator signal using afrequency divider. In addition or alternatively, at least one mixeroscillator signal may also be generated from the common oscillatorsignal using a frequency multiplier (e.g., a frequency doubler). If, forexample, there is a common oscillator signal with a frequency of, forexample, 10 MHz, then a mixer oscillator signal with a frequency of, forexample, 20 MHz and/or a mixer oscillator signal with a frequency of,for example, 5 MHz may be obtained “on board” from this oscillatorsignal. Thus, even with only one single oscillator signal, more thanthree transmission signals may be provided per frequency multiplex,which are then all transmitted via the common high-frequency line. Onlya single oscillator signal is provided for this purpose. The singleoscillator signal may also be supplied via the common high-frequencyline.

A frequency multiplier and/or a frequency divider is also consideredadvantageous if, for example, on account of correspondingspecifications, the LO frequency of the oscillator signal is relativelyclose to one of the frequency bands to be transmitted or relativelyclose to the transmission frequency of one of the transmission signals.With such a frequency multiplier or frequency divider, a mixeroscillator signal may be supplied from the oscillator signal, by whichanother transmission frequency of the transmission signal is generated.

In one embodiment, the oscillator signal is used directly as a mixeroscillator signal for at least one frequency mixer. With the frequencymixer, there is therefore no need for a frequency multiplier and afrequency divider.

In one embodiment, the at least two input signals are provided asreceive signals of a magnetic resonance tomography system. Theadvantages of the method according to one or more of the presentembodiments thus produce the best results because the cabling work forthe magnetic resonance tomography system is significantly reducedcompared with known magnetic resonance devices.

A method for simultaneous transmission of at least two high-frequencytransmission signals via a common high-frequency line—is also provided.The method includes providing at least two input signals to respectiveinlet ports. The input signals are signals of the same carrierfrequency. A transmission signal is provided, from at least one of theinput signals, with a different transmission frequency from the carrierfrequency by mixing the input signal using a frequency mixer. Thetransmission signal is transmitted via the common high-frequency line.One of the input signals is transmitted as a transmission signal unmixedwith the carrier frequency via the common high-frequency line.

In addition, a signal transmission device that is configured to performa method according to one or more of the present embodiments is alsoprovided.

A magnetic resonance tomography system according to one or more of thepresent embodiments includes a signal transmission device.

The embodiments and the advantages of the embodiments presented withregard to the method apply correspondingly to the signal transmissiondevice and to the magnetic resonance tomography system.

Additional features emerge from the claims, the figures and thedescription of the figures. All the aforementioned features andcombinations of features in the description as well as the features andcombinations of features mentioned in the description of the figureshereinafter and/or shown in the figures alone may be used not only inthe respective combination specified, but also in other combinations orin isolation.

BRIEF DESCRIPTION OF THE DRAWINGS

The description below represents embodiments, and the invention is notrestricted to these exemplary embodiments. The features of differentexemplary embodiments according to FIGS. 1 to 5 may be combined witheach other.

FIG. 1 shows one embodiment of a signal transmission device;

FIG. 2 shows another embodiment of a signal transmission device;

FIG. 3 shows yet another embodiment of a signal transmission device;

FIG. 4 shows one embodiment of a signal transmission device; and

FIG. 5 shows another embodiment of a signal transmission device.

DETAILED DESCRIPTION

An embodiment of a signal transmission device 1 shown in FIG. 1 is forthe transmission of, for example, three transmission signals U1, U2, U3in total via a common high-frequency line 2 that, for example, may beconfigured as a coaxial line. FIG. 1 shows a block diagram of the signaltransmission device 1.

The signal transmission device 1 may, for example, form part of amagnetic resonance tomography system. In the exemplary embodiment shownin FIG. 1, the signal transmission device 1 includes a total of threeports 3, 4, 5 that are, for example, each coupled to a local coil of themagnetic resonance tomography system. Input signals E1, E2, E3 that maybe receive signals of the local coils of the magnetic resonancetomography system are provided at the ports 3, 4, 5. The input signalsE1, E2, E3 have the same carrier frequencies of, for example, 21.6 MHz.

So that the input signals E1, E2, E3 may be transmitted via the commonhigh-frequency line 2, a frequency division multiplexing (FDM) method isemployed. For this purpose, the input signals E1, E2, E3 are convertedinto the respective transmission signals U1, U2, U3, which havedifferent transmission frequencies from each other.

In the exemplary embodiment, the first input signal E1 is directlycoupled into the high-frequency line 2 as the transmission signal U1without a frequency conversion so that the first transmission signal U1is transmitted with a transmission frequency of, for example, 21.6 MHz.The first input signal E1 is filtered solely with the aid of a band-passfilter 6 that only permits frequencies of around, for example, 21.6 MHzto pass through. The outlet of the band-pass filter 6 is thereforecoupled to the common high-frequency line 2.

In contrast, the second input signal E2 and the third input signal E3are each mixed with the aid of a frequency mixer 7, 8 and thus convertedinto the respective transmission signals U2, U3. The first frequencymixer 7 is an up converter, while the second frequency mixer 8 is a downconverter. This provides that the second input signal E2 is mixedupward, while the third input signal E3 is mixed downward. A commonoscillator signal LO that has a frequency of, for example, 10 MHz isadded to the frequency mixers 7, 8. The oscillator signal LO is divided,for example, with the aid of a power divider between the two frequencymixers 7, 8 so that a first mixer oscillator signal LO1 is added to thefirst frequency mixer 7, and the second frequency mixer 8 is suppliedwith a second mixer oscillator signal LO2. The following is applicablewith regard to the frequency: LO1=LO2. The mixer oscillator signals LO1,LO2 therefore correspond to the common oscillator signal LO or have thesame frequency of, for example, 10 MHz.

As a result, the second transmission signal U2 has a transmissionfrequency of, for example, 31.6 MHz, while the third transmission signalU3 has a transmission frequency of, for example, 11.6 MHz.

A band-pass filter 9 is also arranged between the second port 4 and thefrequency mixer 7. The second input signal E2 is filtered by theband-pass filter 9 before the signal E2 is supplied to the frequencymixer 7. The band-pass filter 9 only permits frequencies of around, forexample, 21.6 MHz to pass through so that the noise of the imagefrequency band of the frequency mixer 7 is suppressed and consequentlynot mixed into the image frequency band of the frequency mixer 7. Anamplifier 10 is also installed downstream of the frequency mixer 7. Thesecond transmission signal U2 is amplified by the amplifier 10 at, forexample, 31.6 MHz. An additional band-pass filter 11 is also installeddownstream of the amplifier 10, and permits frequencies of around, forexample, 31.6 MHz to pass through. The outlet of the band-pass filter 11is coupled to the common high-frequency line 2.

An additional band-pass filter 12 that permits frequencies of around,for example, 21.6 MHz to pass through is also arranged between the thirdport 5 and the frequency mixer 8 to filter the third input signal E3. Acorresponding amplifier 13 is also installed downstream of the frequencymixer 8, and amplifies the third transmission signal U3 before thistransmission signal U3 is filtered with the aid of an additionalband-pass filter 14. The band-pass filter 14 has a pass frequency of,for example, 11.6 MHz.

The overall amplification of the second and third transmission signalsU2 and U3 may be set at 0 dB so that the signal level of the two pathscorresponds to the signal level of the first transmission signal U1. Thelosses that occur on account of mixing the input signals E2 and E3 aretherefore compensated by the two amplifiers 10, 13.

The following transmission signals may therefore be transmitted via thecommon high-frequency line 2: the transmission signal U1 with thetransmission frequency of 21.6 MHz; the transmission signal U2 with thetransmission frequency of 31.6 MHz; and the transmission signal U3 withthe transmission frequency of 11.6 MHz.

In addition, the common oscillator signal LO, which has a frequency of,for example, 10 MHz, is also transmitted via this common high-frequencyline 2. Before the oscillator signal LO is divided into the mixeroscillator signals LO1, LO2, the oscillator signal LO is filtered withthe aid of a band-pass filter 15. The band-pass filter 15 permitsfrequencies of around, for example, 10 MHz to pass through andsuppresses the frequencies of the transmission signals U1 to U3.

FIG. 2 shows an additional exemplary embodiment of the signaltransmission device 1. The only difference between the signaltransmission device 1 of FIG. 2 and the signals transmission device 1 ofFIG. 1 is that an oscillator signal LO with a frequency of, for example,5 MHz is transmitted via the common high-frequency line 2, and theband-pass filter 15 has a pass frequency of, for example, 5 MHzaccordingly. In order to provide the two mixer oscillator signals LO1,LO2 with a frequency of 10 MHz, a frequency doubler 16, by which thefrequency of the oscillator signal LO is doubled, is used. A signal witha frequency of 10 MHz is therefore found at the output of the frequencydoubler 16.

FIG. 3 shows a signal transmission device 1 that is different from thedevice as per FIG. 2 in that an oscillator signal LO that has afrequency of, for example, 40 MHz is transmitted via the high-frequencyline 2. Accordingly, the band-pass filter 15 is configured such that theband-pass filter 15 permits frequencies of 40 MHz to pass through. Afrequency divider 17 that divides the frequency of the oscillator signalLO by a factor of 4 is used to reduce the frequency of the oscillatorsignal LO to 10 MHz. This provides that a signal that has a frequencyof, for example, 10 MHz is provided at the output of this frequencydivider 17.

A further embodiment of the device 1 is shown in FIG. 4. Thetransmission frequency of the third transmission signal U3 is, forexample, 41.6 MHz. To provide such a transmission frequency, anoscillator signal LO with a frequency of, for example, 10 MHz issupplied via the high-frequency line 2 to the device 1, and is thenconverted into the second mixer oscillator signal LO2 with a frequencyof 20 MHz with the aid of a frequency doubler 16. The frequency mixer 8is an up converter that provides the third transmission signal U3 with afrequency of, for example, 41.6 MHz from the third input signal E3 witha frequency of, for example, 21.6 MHz. Before the frequency doubler 16,the oscillator signal LO is also tapped for the first frequency mixer 7and supplied to the frequency mixer 7 as a first mixer oscillator signalLO1 with a frequency of, for example, 10 MHz. The first frequency mixer7 therefore continues to provide a transmission signal U2 with afrequency of, for example, 31.6 MHz. In the exemplary embodiment as perFIG. 4, the band-pass filter 15 is configured such that the passfrequency of the band-pass filter 15 is, for example, 10 MHz.

FIG. 5 shows a device, in which a total of four transmission signals U1to U4 are transmitted via the common high-frequency line 2. The firstthree transmission signals U1 to U3 correspond to the first threetransmission signals of FIG. 4. An additional port is provided. A fourthinput signal E4 is applied to the additional port. The input signal E4is filtered with the aid of a band-pass filter 19 with a pass frequencyof, for example, 21.6 MHz and is supplied to a further frequency mixer20. The frequency mixer 20 provides the fourth transmission signal U4,which is amplified with the aid of an amplifier 21 and is filtered withthe aid of a band-pass filter 22 with a pass frequency of, for example,51.6 MHz. The fourth transmission signal U4 therefore has a transmissionfrequency of 51.6 MHz. For this purpose, a third mixer oscillator signalLO3, which has a frequency of, for example, 30 MHz, is supplied to thethird frequency mixer 20. The mixer oscillator signal LO3 is generatedfrom the common oscillator signal LO, which has a frequency of, forexample, 10 MHz. The band-pass filter 15 therefore has a pass frequencyof 10 MHz.

In order to convert the oscillator signal LO into the third mixeroscillator signal LO3, a frequency multiplier 23 that multiplies thefrequency of the oscillator signal LO by a factor of 3 is used. Thefrequency mixer 20, similar to the other mixers 7, 8, is an upconverter.

Any number of mixer oscillator signals LO1 to LOn may therefore besupplied from the same oscillator signal LO so that any or a greaternumber of transmission signals may also be transmitted via the commonhigh-frequency line 2. Embodiments shown in FIGS. 1 to 5 may also becombined with each other. If a signal transmission device 1 such as thatshown in FIGS. 1 to 5 is used in a magnetic resonance tomography system,then the cabling is reduced considerably in comparison to the prior art.The feature that one of the input signals (e.g., the signal E1) isdirectly transmitted unmixed as a transmission signal U1 via thehigh-frequency line 2 contributes to this.

The common high-frequency line 2 is coupled on the other side (notshown), for example, with an electronic evaluation device of a magneticresonance tomography system. There, the transmission signals U1 to U4may be individually obtained again by, for example, using correspondingband-pass filters. The signals may be down-mixed in baseband or directlyconverted into digital signals with the aid of an analog-digitalconverter and further processed as such.

It is to be understood that the elements and features recited in theappended claims may be combined in different ways to produce new claimsthat likewise fall within the scope of the present invention. Thus,whereas the dependent claims appended below depend from only a singleindependent or dependent claim, it is to be understood that thesedependent claims can, alternatively, be made to depend in thealternative from any preceding or following claim, whether independentor dependent, and that such new combinations are to be understood asforming a part of the present specification.

While the present invention has been described above by reference tovarious embodiments, it should be understood that many changes andmodifications can be made to the described embodiments. It is thereforeintended that the foregoing description be regarded as illustrativerather than limiting, and that it be understood that all equivalentsand/or combinations of embodiments are intended to be included in thisdescription.

1. A method for simultaneous transmission of at least two high-frequencytransmission signals via a common high-frequency line, the methodcomprising: inputting at least two input signals at respective inletports, wherein the at least two input signals are signals of a samecarrier frequency; generating, from the at least two input signals,respective transmission signals with different transmission frequenciesfrom each other and from a carrier frequency, the generating of therespective transmission signals comprising mixing the at least two inputsignals using one frequency mixer each, wherein the frequency mixers aresupplied with respective mixer oscillator signals; and transmitting thetransmission signals via the common high-frequency line, wherein themixer oscillator signals are provided from a same oscillator signal. 2.The method as claimed in claim 1, wherein inputting at least two inputsignals comprises inputting at least three input signals of the samecarrier frequency, and wherein the method further comprises transmittingone input signal of the at least three input signals as a transmissionsignal unmixed with the carrier frequency via the common high-frequencyline.
 3. The method as claimed in claim 1, further comprisingtransmitting the oscillator signal via the common high-frequency line tothe frequency mixers.
 4. The method as claimed in claim 1, wherein atleast two of the mixer oscillator signals provided from the sameoscillator signal are signals of the same frequency, and wherein a firstof the frequency mixers is an up converter and a second of the frequencymixers is a down converter.
 5. The method as claimed in claim 1, whereinat least one of the mixer oscillator signals is generated from theoscillator signal by a frequency divider.
 6. The method as claimed inclaim 1, wherein at least one of the mixer oscillator signals isgenerated from the oscillator signal by a frequency multiplier.
 7. Themethod as claimed in claim 1, wherein for at least one of the frequencymixers the oscillator signal is used directly as one or the mixeroscillator signals.
 8. The method as claimed in claim 1, wherein the atleast two input signals are provided as receive signals of a magneticresonance tomography system.
 9. A signal transmission device forsimultaneous transmission of at least two high-frequency transmissionsignals via a common high-frequency line, the signal transmission devicecomprising: at least two inlet ports operable to provide at least tworespective input signals, wherein the at least two input signals aresignals of a same carrier frequency; at least two frequency mixersoperable to provide, from the at least two input signals, respectivetransmission signals with different transmission frequencies from eachother and from a carrier frequency by mixing the at least two inputsignals, wherein the at least two frequency mixers are supplied withrespective mixer oscillator signals; and the common high-frequency lineoperable transmit the transmission signals, wherein the mixer oscillatorsignals are provided from a same oscillator signal.
 10. The signaltransmission device as claimed in claim 9, wherein the at least twoinlet ports comprise at least three input ports operable to provide atleast three respective input signals of the same carrier frequency, andwherein the common high-frequency line is operable to transmit one inputsignal of the at least three input signals as a transmission signalunmixed with the carrier frequency.
 11. The signal transmission deviceas claimed in claim 9, wherein the common high-frequency line isoperable to transmit the oscillator signal to the frequency mixers. 12.The signal transmission device as claimed in claim 9, wherein at leasttwo of the mixer oscillator signals provided from the same oscillatorsignal are signals of the same frequency, and wherein a first of thefrequency mixers is an up converter and a second of the frequency mixersis a down converter.
 13. The signal transmission device as claimed inclaim 9, further comprising a frequency divider operable to generate atleast one of the mixer oscillator signals from the oscillator signal.14. The signal transmission device as claimed in claim 9, furthercomprising a frequency multiplier operable to generate at least one ofthe mixer oscillator signals from the oscillator signal.
 15. A magneticresonance tomography system comprising: a signal transmission device forsimultaneous transmission of at least two high-frequency transmissionsignals via a common high-frequency line, the signal transmission devicecomprising: at least two inlet ports operable to provide at least tworespective input signals at, wherein the at least two input signals aresignals of a same carrier frequency; at least two frequency mixersoperable to provide, from the at least two input signals, respectivetransmission signals with different transmission frequencies from eachother and from a carrier frequency by mixing the at least two inputsignals, wherein the at least two frequency mixers are supplied withrespective mixer oscillator signals; and the common high-frequency lineoperable transmit the transmission signals, wherein the mixer oscillatorsignals are provided from a same oscillator signal.
 16. The magneticresonance tomography system as claimed in claim 15, wherein the at leasttwo inlet ports comprise at least three input ports operable to provideat least three respective input signals of the same carrier frequency,and wherein the common high-frequency line is operable to transmit oneinput signal of the at least three input signals as a transmissionsignal unmixed with the carrier frequency.
 17. The magnetic resonancetomography system as claimed in claim 15, wherein the commonhigh-frequency line is operable to transmit the oscillator signal to thefrequency mixers.
 18. The magnetic resonance tomography system asclaimed in claim 15, wherein at least two of the mixer oscillatorsignals provided from the same oscillator signal are signals of the samefrequency, and wherein a first of the frequency mixers is an upconverter and a second of the frequency mixers is a down converter. 19.The magnetic resonance tomography system as claimed in claim 15, whereinthe signal transmission device further comprising a frequency divideroperable to generate at least one of the mixer oscillator signals fromthe oscillator signal.
 20. The magnetic resonance tomography system asclaimed in claim 15, wherein the signal transmission device furthercomprising a frequency multiplier operable to generate at least one ofthe mixer oscillator signals from the oscillator signal.